A monolithic ceramic capacitor is an electronic component used for circuits of a wide variety of electronic devices, and along with miniaturization of the electronic devices, miniaturization of the monolithic ceramic capacitor has been required.
The monolithic ceramic capacitor is produced by laminating units in which an internal electrode is interposed between one dielectric layer and another dielectric layer and sintering the laminate. In order to miniaturize the monolithic ceramic capacitor without reducing the capacity of the monolithic ceramic capacitor, it is necessary that the dielectric layers are made thinner.
However, if the dielectric layer is made thinner, a voltage with high field strength is applied to the dielectric layer. Therefore, in some cases, reduction of dielectric constant and deterioration of temperature characteristic may occur and a high-temperature load life may be reduced, so that deterioration of reliability may occur.
Consequently, it is necessary to realize a dielectric ceramic having a large dielectric constant and good temperature characteristic and exhibiting excellent reliability even when a voltage with high field strength is applied because of reduction in thickness of the dielectric layer.
Accordingly, a dielectric ceramic having a composition, which includes a primary component composed of a perovskite compound represented by ABO3 (where A represents Ba and Ca, or Ba, Ca, and Sr, B represents at least one type of Ti, Ti and Zr, and Hf) and an additive component containing Si, a predetermined rare earth element R, and a predetermined metal element M, and including crystal grains and crystal grain boundaries present between crystal grains, has been hitherto proposed, wherein the above-described additive component is not contained as a solid solution, and the above-described primary component is present, in regions of 90% or more of the cross-sections of crystal grains constituting 85% or more, on the number basis, of the above-described crystal grains, and wherein at least the above-described Ba, Ca, Ti, Si, R, and M are contained in analytical points constituting 85% or more, on the number basis, of analytical points at the above-described crystal grain boundaries (Patent Document 1).
In Patent Document 1, it is intended that a high-temperature load life is ensured by including (Ba,Ca)TiO3 as a primary component and Si, a predetermined rare earth element R, and a predetermined metal element M as secondary components, and allowing the above-described secondary components to present at crystal grain boundaries while forming almost no solid solution with the primary component and, thereby, the reliability is improved.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2004-224653